Ram Air Turbine (RAT) systems are used in contemporary aircraft as emergency or supplemental power systems. They typically have a turbine, with a rotating hub and a plurality of blades, operably coupled to an electric generator to provide the driving source for the generator. Initially in flight they are stowed in a compartment of the aircraft fuselage, covered by a compartment door. When needed as a source of emergency or supplemental power, the RAT system is deployed from the fuselage into the surrounding airstream, which drives the blades to rotate the generator to extract energy from the airstream. As power requirements for aircraft systems increase, the power generation capabilities of RAT systems continue to increase.
RAT systems can also be configured to operate in predetermined conditions, such as when exposed to environmental debris, such as volcanic ash. In such a configuration, RAT systems can be fully enclosed or sealed to prevent the debris from entering the generator, where it can cause machine performance degradation or malfunction. However, such enclosing or sealing can interfere with active or passive cooling systems, for example, liquid coolant systems, as such sealing can prevent, inhibit, or interfere with conventional cooling or heat removal pathways. Specifically, difficulty in cooling the rotor can lead to reduced generator performance or generator failure.